Dynastarter Question
Dynastarter Question
(OP)
So its a basic motor. Everything seems insulated. I put it together up to the negative brushes and I can connect a power wire to it and the casing and armature still is grounded. It is not till I connect the Positve brushes which have insulated seats that the whole system including the casing becomes a positive charge. Touch any part of it to a ground and you get a nasty spark.
I cleaned the commutator and still it carries current across the segments. Is that supposed to happen? Or would the short be somewhere else and perhaps multiple areas?
I cleaned the commutator and still it carries current across the segments. Is that supposed to happen? Or would the short be somewhere else and perhaps multiple areas?





RE: Dynastarter Question
Permanent magnet?
Series?
Shunt?
An armature is almost a short circuit (very low resistance) until the motor starts spinning and starts generating aback EMF to reduce the current.
Bill
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"Why not the best?"
Jimmy Carter
RE: Dynastarter Question
RE: Dynastarter Question
RE: Dynastarter Question
Don't let it run for more than a fraction of a second without a load; it will _really_ spool up. For that reason, tie it down, too.
Mike Halloran
Pembroke Pines, FL, USA
RE: Dynastarter Question
RE: Dynastarter Question
What you are seeing, sparking and a very low resistance between com segments, is normal for both a good starter and a bad starter. Use a megger to check for ground faults. Use a "growler" to check for shorted windings in the commutator.
OR
Take the starter to a rewind shop.
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Dynastarter Question
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If we learn from our mistakes I'm getting a great education!
RE: Dynastarter Question
If this is true for your starter, then there is only one large (>300 amp, >3/8") terminal that is connected to the positive brushes. The negative brushes are connected to the series field. The series field is then connected to the starter case internally.
If this is the case, then you should be able to make the following ohmic readings:
- lift all brushes: positive terminal, armature, and case are all isolated from each other.
- install positive brushes only: positive terminal is common to armature, case is isolated from armature and positive terminal.
- install negative brushes only: positive terminal is isolated from armature and case, armature and case are common.
If these tests confirm that you have a series connected, single terminal, starter motor, then you can run it by doing the following.
Connect the power supply between the positive terminal and the starter case. When you do this, the starter should run and there should be no spark between the case and ground (assuming the power supply ground equals the real ground.)
However, as MikeHalloran suggested, do not do this for long since the speed without load for a series motor is high enough to destroy the motor. Also, fasten the motor to something solid since the acceleration torgue of the starter will make it jump and roll when it is engaged.
Of course, my auto mechanic experience was a long time ago. At the time, I knew nothing about motors and very little about electricity. So, I hope this helps but, please forgive me if I am wrong.
RE: Dynastarter Question
But if that motor hasn't run by now, it may be time to chuck it. Some of UncleBrads's sparks should have resulted in a good motor spinning at least briefly by now.
Bill
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"Why not the best?"
Jimmy Carter
RE: Dynastarter Question
Hope this link helps.
http://ww
RE: Dynastarter Question
RE: Dynastarter Question